<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
</head>
<body>
    <!-- <div class="box1"></div>
    <div class="box2"></div> -->
    <!-- <div class="box1">
        <div class="box2" ></div>
        <div style="clear: both;">bbbbbb</div>
    </div>
    aaaaaa -->
    <div class="box1" clearfix>
        <div class="box2"></div>
    </div>
    aaaaa
</body>
<style>
    /* body{
        border: 1px solid blueviolet;
    } */
    /* .box1{
        width: 100px;
        height: 100px;
        background: pink;
        float: left;
    }
    .box2{
        width: 200px;
        height: 200px;
        background: paleturquoise;
        clear: both;
    } */
    .box1{
        width: 200px;
        border: 1px solid yellowgreen;
    }
    .box2{
        width: 100px;
        height: 100px;
        background: pink;
        float: left;
    }
    .clearfix::after{
        content: "";
        clear: both;
        display: block;
    }
</style>
</html>